Electronic device including flexible display and method for operating the same

According to various embodiments, there may be provided an electronic device comprising: a housing, a flexible display having a resizable region visible to an outside of the housing by at least a portion being moved from the inside to the outside of the housing, a communication circuit configured to enable transmitting or receiving data to or from an external electronic device, at least one sensor configured to identify a size of a region where the flexible display is visible to the outside of the housing, a memory, and at least one processor, wherein the at least one processor is configured to: control the display to display a first content on first region of the flexible display visible to the outside of the housing, establish communication connection with an external electronic device through the communication circuit, transmit, based on the establishing of the communication connection, first information on the first content to the external electronic device through the communication circuit so that the external electronic device displays the first content, when a second region where the flexible display located inside the housing is visible to the outside of the housing, display second content on a third region including the first region and the second region, based on at least one value obtained using the at least one sensor, identify second information on the second content, to be transmitted to the external electronic device, based on the obtained at least one value, and transmit the identified second information to the external electronic device through the communication circuit so that the external electronic device displays the second content.